1. Field of the Invention
The present invention relates to a composition for preventing or alleviating skin wrinkles containing honeybush (Cyclopia intermedia) extract, the fraction thereof, or fermented honeybush as an active ingredient.
2. Description of the Related Art
As getting old, human skin is also aged and the most representative symptom of skin aging is wrinkle. Wrinkle is a phenomenon showing aging. The major mechanism involved in skin wrinkle formation is explained as follows: When skin is continuously exposed on oxidative stress coming from toxic environment such as air pollution, UV exposure, stress or disease, body radical is increased to destroy collagen, elastin, and hyaluronic acid, which are dermal connective tissues, and thereby settling of a certain part of skin (wrinkle) occurs. Such mechanism can further oxidize lipids in cell membrane, resulting in cell destruction with causing such diseases as dermatitis, acne, and skin cancer.
Cause of wrinkle, according to the structure of skin, is explained in more detail hereinafter. Skin structure is largely composed of epidermis and dermis. Epidermis is a thin protective layer composed of keratinocytes, melanocytes, and Langerhans cells. Dermis is a thicker and more complicated layer composed of connective tissues and fibrous tissues comprising collagen and elastic fibers. Collagen is a major structural protein of skin which is responsible for tensile strength and toughness, while elastic fiber plays an important role in skin resilience and skin elasticity.
When turn-over of keratinocytes is decreased in epidermis, stratum corneum is accumulated and thereby the stratum corneum becomes thicker and loses moisture retaining capacity. So, keratin becomes hardened and as a result wrinkle is generated. The dermoepidermal junction area is importantly involved in epidermal cell support, attachment, nutrients transfer, and regulation of epidermal differentiation. Collagen IV and VII can be decreased by the causes of aging, and particularly by UV. At this time, epidermis and dermis supporting role of collagen is weakened and so is selective transmission function. Then, toxic components can affect dermis easily to cause wrinkles (Keene D R et al., The Journal of Cell Biology 1987 104(3):611-621).
Dermis is the tissue comprising connective tissues down the epidermis, which is not as compact as keratinocytes, the epidermal cells, and has extracellular open space. That is, the dermis is composed of network structure of macromolecules called extracellular matrix. The said extracellular matrix is generated by fibroblasts in the dermis and composed of fibrous proteins such as collagen and elastin and polysaccharides called acid mucopolysaccharides such as hyaluronic acid. The connective tissues involved in skin wrinkle formation are the fibrous components such as collagen fiber, reticular fiber, and elastic fiber. Collagen and elastin are elaborately cooperating in the dermis to maintain skin flexibility and elasticity.
Collagen is the fibrous tissue responsible for skin flexibility, which takes approximately 70% of total dermal tissue. As a major element composing skin, collagen is involved in mechanical rigidity, tissue coherence, cell attachment, and cell differentiation in the dermal layer.
The basic role of skin is to keep moisture from evaporating from human body and to prevent the invasion of foreign toxic materials. Since skin is always exposed on external stimuli, it necessarily has many defense mechanisms. Skin is a kind of expression of beauty. That is, healthy and clear skin is accepted as a sign of beauty. Recently, it is not only women but also men who are interested in skin trouble including skin aging, and therefore skin care products are rush to be developed.
To reduce skin wrinkles, ascorbic acid, α-tocopherol, retinol and its derivatives, and super oxide dismutase (SOD) are included in cosmetics or medicines as a free radical scavenger or a skin wrinkle remover, in order to prevent wrinkles and other skin diseases. However, these materials have disadvantages of high price and chemical instability, which makes them non-practical. Therefore, the development of a material that is safer and more effective in alleviating skin wrinkles has been an important target of study not only in the medicinal and food industry but also in cosmetic industry.
Retinoids used for cosmetic compositions for alleviating skin wrinkles are exemplified by retinol, retinal, retinoic acid, retinyl acetate, retinyl linoleate, and retinyl palmitate, etc. Among them, retinol is an endogenous compound which is essential for the differentiation and growth of epithelial tissue. Compared with such retinoids as retinoic acid, etc, retinol is highly stable, which makes it as an excellent, appropriate raw material of cosmetics for alleviating skin wrinkles.
It has been proved by clinical tests for skin that the said retinoid is effective in alleviating skin wrinkles. However, when it is added in a skin care product, it might cause changes in color and scent of the product. In addition, even with a small dose, it can cause side effects such as skin irritation. Titer reduction caused by changes of the properties and following effectiveness decrease are other problems.
To overcome the said problems of the retinoid, it is required to develop a cosmetic composition for alleviating wrinkles using bioactive materials originated from natural substances. Such bioactive materials are advantageous in the points of less side effects on skin and less chemical changes of the properties, indicating that they are excellent in stability and safety. Therefore, studies have been focused on using medicinal plants for the development of a cosmetic composition for preventing or alleviating skin wrinkles.
Honeybush (Cyclopia intermedia) is an evergreen shrub belonging to Melianthaceae, which is only distributed in a narrow area of mountain ridge at east-west seashore in Cape region of South Africa and has a great similarity with Rooibos. The name ‘honeybush’ is given to Cyclopia intermedia because the flower of it smells honey. The way of eating this herb or the effect of it is similar to that of Rooibos, but the taste is much sweeter than Rooibos. Honeybush is processed mainly as a tea. It contains a small amount of tannin but has no caffeine at all. Instead, honeybush contains various minerals (for example, iron, potassium, calcium, copper, zinc, magnesium, etc). It has been used to treat cold, insomnia, and stomachache since long before and known to have blood sugar reducing effect. In the description of PCT/EP2008/052863, anti-diabetic effect of honeybush extract is described. According to a previous report, honeybush extract can control the differentiation of esophageal papilloma (Sissing L et al., Nutrition and cancer 2011 63(4):600-610). However, it is still unknown whether or not honeybush extract has the effect of alleviating skin wrinkles.
The present inventors studied to develop natural plant extracts to alleviate skin wrinkles. As a result, the present inventors confirmed that the honeybush extract or fermented honeybush could reduce the length and depth of skin wrinkles caused by UV irradiation and reduce the thickness of the epidermal layer, in addition to suppress collagen tissue breakdown reaction, suggesting skin wrinkle alleviating effect. Accordingly, the present inventors completed this invention by confirming that the honeybush extract or fermented honeybush could be effectively used as an active ingredient of a composition for preventing or alleviating skin wrinkles.